#include<stdio.h>
#include<unistd.h>

int g_val = 100;

int main()
{
   printf("g_val: %d, &g_val: %p\n", g_val, &g_val);

   pid_t id = fork();
   if(id == 0)
   {
     while(1)
     {
       printf("我是子进程，pid: %d, ppid: %d, g_val: %d, &g_val: %p\n", getpid(), getppid(), g_val, &g_val);
       sleep(1);
       g_val++;
     }
   }
   else
   {
     while(1)
     {
       printf("我是父进程，pid: %d, ppid: %d, g_val: %d, &g_val: %p\n", getpid(), getppid(), g_val, &g_val);
       sleep(1); 
     }
   }
}
